Washing equipments in which ultrasonic wave transmitter is utilized belong to prior art. In case of these washing equipments, matters to be washed are placed in a treatment tank and are irradiated by ultrasonic waves from an oscillator mounted on a wall or at the bottom of said tank for a certain predetermined interval. Namely, the washing method is limited only to batch treatment. Therefore, it requires much time and many troubles that matters to be washed are brought in or taken out of said tank. This kind of conventional washing equipments requires further wash-out treatment for which another separate device or manned work is indispensable. So, it is complicated or troublesome to wash and treat such plates or matters.